text: /* $Id: strtoul.c,v 1.1 2009-07-27 21:27:52 dave Exp $ */
  
  /*
   * Copyright (c) 1990, 1993
   *	The Regents of the University of California.  All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of the University nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  
  #if 0
  static char sccsid[] = "@(#)strtoul.c	8.1 (Berkeley) 6/4/93";
  __RCSID("$NetBSD: strtoul.c,v 1.16 2003/08/07 16:43:45 agc Exp $");
  #endif
  
  #include <ctype.h>
  #include <errno.h>
  #include <limits.h>
  #include <stdlib.h>
  
  /*
   * Convert a string to an unsigned long integer.
   *
   * Ignores `locale' stuff.  Assumes that the upper and lower case
   * alphabets and digits are each contiguous.
   */
  unsigned long
  strtoul(const char *nptr, char **endptr, int base)
  {
  	const char *s;
  	unsigned long acc, cutoff;
  	int c;
  	int neg, any, cutlim;
  
  	/*
  	 * See strtol for comments as to the logic used.
  	 */
  	s = nptr;
  	do {
  		c = (unsigned char) *s++;
  	} while (isspace(c));
  	if (c == '-') {
  		neg = 1;
  		c = *s++;
  	} else {
  		neg = 0;
  		if (c == '+')
  			c = *s++;
  	}
  	if ((base == 0 || base == 16) &&
  	    c == '0' && (*s == 'x' || *s == 'X')) {
  		c = s[1];
  		s += 2;
  		base = 16;
  	}
  	if (base == 0)
  		base = c == '0' ? 8 : 10;
  
  	cutoff = ULONG_MAX / (unsigned long)base;
  	cutlim = (int)(ULONG_MAX % (unsigned long)base);
  	for (acc = 0, any = 0;; c = (unsigned char) *s++) {
  		if (isdigit(c))
  			c -= '0';
  		else if (isalpha(c))
  			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
  		else
  			break;
  		if (c >= base)
  			break;
  		if (any < 0)
  			continue;
  		if (acc > cutoff || (acc == cutoff && c > cutlim)) {
  			any = -1;
  			acc = ULONG_MAX;
  			errno = ERANGE;
  		} else {
  			any = 1;
  			acc *= (unsigned long)base;
  			acc += c;
  		}
  	}
  	if (neg && any > 0)
  		acc = -acc;
  	if (endptr != 0)
  		/* LINTED interface specification */
  		*endptr = (char *)(any ? s - 1 : nptr);
  	return (acc);
  }
  